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Chinese Physics B 2024年第10期33卷 295-301页

作者： Kunqi Huang Yiran Lin Yun Lai Xiaozhou Liu key laboratory of modern acoustics Institute of AcousticsNanjing UniversityNanjing 210093China School of Physics Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China state key laboratory of acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

Phononic crystals,as artificial composite materials,have sparked significant interest due to their novel characteristics that emerge upon the introduction of *** these properties,second-harmonic features exhibit potential applications in acoustic frequency conversion,non-reciprocal wave propagation,and non-destructive *** manipulating the harmonic band structure presents a major challenge in the design of nonlinear phononic *** design approaches based on parameter adjustments to meet specific application requirements are inefficient and often yield suboptimal ***,this paper develops a design methodology using Softmax logistic regression and multi-label classification learning to inversely design the material distribution of nonlinear phononic crystals by exploiting information from harmonic transmission *** results demonstrate that the neural network-based inverse design method can effectively tailor nonlinear phononic crystals with desired *** work establishes a mapping relationship between the band structure and the material distribution within phononic crystals,providing valuable insights into the inverse design of metamaterials.

关键词： multi-label classification learning nonlinear phononic crystals inverse design

The higher-order topological pumping explored in the 2D acoustic crystal

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Science china(Physics,Mechanics & Astronomy) 2024年第2期67卷 127-133页

作者： Yanqiu Wang Bin Liang Jianchun Cheng key laboratory of modern acoustics Ministry of EducationInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

The topological pumping has been instrumental in advancing our understanding of topological phase transitions in various physical systems,which can be extended to uncover intriguing higher-order topological phases in the lower-dimensional ***,we propose a theoretical exploration of topological dipole pumping on an acoustic square superlattice by cyclically modulating intracell couplings,which shares the topological nature of an extended three-dimensional system with chiral hinge *** the multipole chiral numbers,we characterize the higher-order topological phases that arise during the *** evolution of topological phase transitions is verified by numerical simulations and shows corner states are transferred across the *** findings can inspire the construction of chiral hinge states in artificial crystals,opening up new possibilities for the design of devices allowing the unidirectional propagation of sound.

关键词： topological phases of matter Thouless pumping acoustic metamaterial

Random Subspace Sampling for Classification with Missing Data

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Journal of Computer Science & Technology 2024年第2期39卷 472-486页

作者：曹云浩吴建鑫 state key laboratory for Novel Software Technology Nanjing UniversityNanjing 210093China

Many real-world datasets suffer from the unavoidable issue of missing values,and therefore classification with missing data has to be carefully handled since inadequate treatment of missing values will cause large *** this paper,we propose a random subspace sampling method,RSS,by sampling missing items from the corresponding feature histogram distributions in random subspaces,which is effective and efficient at different levels of missing *** most established approaches,RSS does not train on fixed imputed ***,we design a dynamic training strategy where the filled values change dynamically by resampling during ***,thanks to the sampling strategy,we design an ensemble testing strategy where we combine the results of multiple runs of a single model,which is more efficient and resource-saving than previous ensemble ***,we combine these two strategies with the random subspace method,which makes our estimations more robust and *** effectiveness of the proposed RSS method is well validated by experimental studies.

关键词： missing data random subspace neural network ensemble learning

Cyclic Beam Direction of Arrival Estimation Method for Ship Propeller Noise

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Journal of Ocean university of china 2024年第4期23卷 883-896页

作者： ZHANG Xiaowei NIE Weihang XU Ji YAN Yonghong The key laboratory of Speech acoustics and Content Understanding Institute of AcousticsChinese Academy of SciencesBeijing 100190China The key laboratory of Speech acoustics and Content Understanding Institute of AcousticsUniversity of Chinese Academy of SciencesBeijing 100049China The state key laboratory of acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

In underwater acoustic applications,the conventional cyclic direction of arrival algorithm faces challenges,including a low signal-to-noise ratio and high bandwidth when compared with modulated *** response to these issues,this paper introduces a novel,robust,and broadband cyclic beamforming *** proposed method substitutes the conventional cyclic covariance matrix with the variance of the cyclic covariance matrix as its primary *** that the same frequency band shares a common steering vector,the new algorithm achieves superior detection performance for targets with specific modulation frequencies while suppressing interference signals and background *** results demonstrate a significant enhancement in the directibity index by 81%and 181%when compared with the traditional Capon beamforming algorithm and the traditional extended wideband spectral cyclic MUSIC(EWSCM)algorithm,***,the proposed algorithm substantially reduces computational complexity to 1/40th of that of the EWSCM algorithm,employing frequency band statistical averaging and covariance matrix variance.

关键词： cyclostationarity direction of arrival extended wideband spectral cyclic music cyclic covariance matrix

A Self-Healing Elastomer with Extremely High Toughness Achieved by Acylsemicarbazide Hydrogen Bonding and Cu^(2+)-Neocuproine Coordination Interactions

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Chinese Journal of Polymer Science 2024年第10期42卷 1425-1434,I0007页

作者： Xiao-Ming An Yi-Ping Wang Tang-Song Zhu Chong Xing Xu-Dong Jia Qiu-Hong Zhang key laboratory of High Performance Polymer Material and Technology of MOE Department of Polymer Science and EngineeringSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing210093China state key laboratory of Coordination Chemistry Nanjing UniversityNanjing210093China

Elastomers with high mechanical toughness can guarantee their durability during service ***-healing ability,as well as recyclability,can also extend the life of materials and save the consuming cost of the *** efforts have been dedicated to promoting the mechanical toughness as well as the self-healing capability of elastomers at the same time,while it remains a challenge to balance the trade-off between the above properties in one *** we proposed a molecular design driven by dual interactions of acylsemicarbazide hydrogen bonding and Cu^(2+)-neocuproine coordination *** introducing the reversible multiple hydrogen bonds and strong coordination bonds,we successfully fabricated an extremely tough and self-healing *** elastomer can achieve an impressive top-notch toughness of 491 MJ/m^(3).Furthermore,it boasted rapid elastic restorability within 10 min and outstanding crack tolerance with high fracture energy(152.6kJ/m^(2)).Benefiting from the combination of dynamic interactions,the material was able to self-repair under 80℃conveniently and could be reprocessed to restore the exceptional mechanical properties.

关键词： Metal-ligand coordination Hydrogen bond Ultra-tough elastomer Self-healing

Robust and Tunable Ferroelectricity in Ba/Co Codoped (K_(0.5)Na_(0.5))NbO_(3) Ceramics

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Chinese Physics Letters 2024年第7期41卷 152-160页

作者：刘佳讯查节林杨玉龙吕笑梅胡雪莉阎朔吴子敬黄凤珍 National laboratory of Solid state Microstructures and School of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

The 0.98(K_(0.5)Na_(0.5))NbO_(3)-0.02Ba(Nb_(0.5)Co_(0.5))O_(3-δ) ceramics with doped Ba^(2+) and Co^(2+) ions are fabricated,and the impacts of the thermal process are *** with the rapidly cooled (RC) sample,the slowly cooled (SC) sample possesses superior dielectric and ferroelectric properties,and an 11 K higher ferroelectricparaelectric phase transition temperature,which can be attributed to the structural characteristics such as the grain size and the degree of *** treatment can reversibly modulate the content of the oxygen vacancies,and in turn the ferroelectric hysteresis loops of the ***,robust and tunable ferroelectric property is achieved in SC samples with good structural integrity.

关键词： ceramics ferroelectric treatment

Coexistence of All-Order Topological states in a Three-Dimensional Phononic Topological Crystalline Insulator

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Research 2024年第2期2023卷 511-518页

作者： Hua-Shan Lai Hao Chen Chu-Hao Xia Si-Yuan Yu Cheng He Yan-Feng Chen National laboratory of Solid state Microstructures&Department of Materials Science and Engineering Nanjing UniversityNanjng 210093China Collaborative Innovation Center of Advanced Microstructures nanjing university Nanjng 210093China Jiangsu key laboratory of Artificial Functional Materials nanjing university Nanjing 210093China

Classical-wave topological materials lacking intrinsic half-integer spins are less robust while more ***,we explore a single 3-dimensional phononic topological crystalline insulator that simultaneously exhibits a whole family of first-order quadratic surface,second-order hinge,and third-order corner states within the same *** a topological crystalline insulator hosting all-order phases originates from the different topological nature when hierarchically projected onto different facets and lower dimensions,thus free from trivial cladding *** work offers an ideal platform for either robust wave propagation or localization in on-demand dimensions and may facilitate dimension division multiplexing technology.

关键词： topological dimensions crystalline

Magnetic Nonreciprocity in a Hybrid Device of Asymmetric Artificial Spin-Ice-Superconductors

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Chinese Physics Letters 2024年第6期41卷 119-127页

作者：李冲黄培源王晨光李浩杰吕阳阳岳文诚袁子雄李甜雨涂学凑陶涛董思宁何亮贾小氢孙国柱康琳王华兵吴培亨王永磊 Research institute of Superconductor Electronics Nanjing UniversityNanjing 210093China Purple Mountain Laboratories Nanjing 211111China National key laboratory of Spintronics Nanjing UniversitySuzhou 215163China

Controlling the size and distribution of potential barriers within a medium of interacting particles can unveil unique collective behaviors and innovative *** introduce a unique superconducting hybrid device using a novel artificial spin ice structure composed of asymmetric *** structure forms a distinctive superconducting pinning potential that steers unconventional motion of superconducting vortices,thereby inducing a magnetic nonreciprocal effect,in contrast to the electric nonreciprocal effect commonly observed in superconducting ***,the polarity of the magnetic nonreciprocity is in situ reversible through the tunable magnetic patterns of artificial spin *** findings demonstrate that artificial spin ice not only precisely modulates superconducting characteristics but also opens the door to novel functionalities,offering a groundbreaking paradigm for superconducting electronics.

关键词： artificial collective reciprocal

Heralded entanglement between error-protected logical qubits for fault-tolerant distributed quantum computing

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Science china(Physics,Mechanics & Astronomy) 2024年第2期67卷 25-33页

作者： Jialun Li Zhihao Xie Yachen Li Yansen Liang Zhenhua Li Tao Li MIIT key laboratory of Semiconductor Microstructure and Quantum Sensing School of PhysicsNanjing University of Science and TechnologyNanjing 210094China National laboratory of Solid state Microstructures Nanjing UniversityNanjing 210093China

Quantum error correction is essential for achieving reliable quantum information processing tasks,as it can mitigate the detrimental effects of noise by encoding single-qubit information into a larger quantum ***,the generation of distributed entanglement between logical qubits located within two spatially separated nodes presents a significant resource-intensive challenge that has yet to be *** we present a heralded protocol for generating distributed entanglement between two nonlocal error-protected logical qubits.A high-dimensional single photon can evolve physical qubits into a logical qubit that entangles with the photon and then converts logical qubit-photon entanglement into entanglement between two logical qubits,when the photon state is properly tuned and an effective photon-spin interface between single photons and individual spins is ***,the success of the entanglement generation is heralded by the detection of the photon,and the corresponding efficiency can,in principle,approach *** distinguished features make our protocol highly appealing for future large-scale quantum technologies.

关键词： quantum networks distributed entanglement error-protected logical qubits high-dimensional photons

Tailoring electron vortex beams with customizable intensity patterns by electron diffraction holography

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Opto-Electronic Advances 2024年第2期7卷 14-21页

作者： Pengcheng Huo Ruixuan Yu Mingze Liu Hui Zhang Yan-qing Lu Ting Xu National laboratory of Solid-state Microstructures and Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China College of Engineering and Applied Sciences Key Laboratory of Intelligent Optical Sensing and Manipulation and Jiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210093China

An electron vortex beam(EVB) carrying orbital angular momentum(OAM) plays a key role in a series of fundamental scientific researches, such as chiral energy-loss spectroscopy and magnetic dichroism spectroscopy. So far, almost all the experimentally created EVBs manifest isotropic doughnut intensity patterns. Here, based on the correlation between local divergence angle of electron beam and phase gradient along azimuthal direction, we show that free electrons can be tailored to EVBs with customizable intensity patterns independent of the carried OAM. As proof-of-concept, by using computer generated hologram and designing phase masks to shape the incident free electrons in the transmission electron microscope, three structured EVBs carrying identical OAM are tailored to exhibit completely different intensity patterns. Furthermore, through the modal decomposition, we quantitatively investigate their OAM spectral distributions and reveal that structured EVBs present a superposition of a series of different eigenstates induced by the locally varied geometries. These results not only generalize the concept of EVB, but also demonstrate an extra highly controllable degree of freedom for electron beam manipulation in addition to OAM.

关键词： electron vortex beam orbital angular momentum diffraction holography